Cable terminal for arc lamps



May 29, 1923.

T. F. UHLEMANN CABLE TERMINAL FOR ARC LAMPS Filed Nov. 29 1918 ,4 ATTORNEY Patented May 29, 1923. v

UNITED STATES 1,456,746 PATENT OFFICE.

THEODORE F. UHLEMANN, OF NEW YORK, N. Y., ASSIGNOR TO NICHOLAS POWER COMPANY, OF NEW YORK, N. Y.,

A CORPORATION 01 DELAWARE.

CABLE TERMINAL FOR ABC LAMPS.

To all whom it may co'rwem:

Be it known that I, Tnnononn F. UHLE- MANN, a citizen of the United States, and a resident of the city, county, and State of New York, have invented new and useful Improvements in Cable Terminals for Are Lamps, of which the following is a specification.

This invention relates to improvements in terminal connectors for electrlcally operated devices, particularly arc lamps such as employed in the projection of motion pictures;

The object of the invention is to provide a cable-receiving clamp which may be constructed as an integral part of the bracket arm of the carbon holder and which will, without materially adding to the cost of the bracket arm, provide a convenient clamp for the end of the current-conducting cable having ample conducting area even though made throughout of iron instead of metals of greater conductivity and much hlgher cost.

A further object of the invention is to provide a connecting clamp of this character which is adapted to receive and eificiently clamp cables varying considerably in size without preliminary adjustment of any parts of the clamp.

A further object of the invention is to provide a device of this character which is so designed as to be made throughout, except for the clamping screw, of castings requiring little or no machining in finishing the article for use.

lVith the above objects in view, my invention consists in the construction shown.

in the accompanying drawings herein described. In the said drawings,

Figure 1 is a perspective view of a portion of an arc lamp showing the carbon-holdin bracket arm provided with my improved terminal for the electrical conductor;

Fig. 2 is an enlarged front elevation of the end of the bracket arm on which the terminal is formed;

Fig. 3 is a plan view of the portion of the bracket arm shown in Fig. 2;

Fig. 4 is a similar view with the upper portions of the terminal removed; and

Fig. 5 is an inverted plan view of the upper clamping member of the cable grip.

eferring to the drawings, particularly to Fig. 1, indicates the supporting memjections and depressions of the two clampher for the arc lamp here shown oonven tionall as a post carrying on its lower end a brac et 2 for the attachment of the lower carbon knuckle. The carbon knuckle comprises a transverse plate 5'insulated from the bracket by an interposed sheet 4 of mica or other suitable material and is pro-' vided with a projecting arm 6 to which the end of the grip member 7 is adjustably connected in the usual manner.

The end of the electrical conductor '8 through which the current is conducted. to the carbon 9 is attached to the end of the plate 5, for which purpose the plate is extended beyond the end of the corresponding plate 2 and has formed integral with it one member 10 of the 2-part grip for the cable. The member 10 comprises an enlarged flat jaw having a V-shaped depression 11 extending in a direction transverse to the face of the plate 5, the metal of the jaw at each side of the depression 11 projecting above the face of the jaw in ridges 1-2.

At intervals along the ridges 12 there are provided V-sha d depressions 13 for re- 80 ceiving interloc ing projections 14 on the under face of the cooperating clampingmember 15. The depressions 13, of which there are four. in number, divide the ridges into six projections 16 which are designed to fit into the complementary depressions 17 formed on the under face of the clamping member 15 and alternating with the projections 14. More briefly stated, the proing members are arranged to be complementary one of the other, so that the V-shaped middle groove 11 of the lower clamping member forms with the corresponding groove 18 on the under face'of the upper clamping member a square socket for the main portion of the cable, which socket may be materially altered in cross sectional area 7 while still confining the cable on the edges.

When the clamp is contracted as far as ossible the width of the side of the square ore will be equal to the face of the middle groove 11 at the depression 13, while in its most extended position the sides of the square will be equal to the full depth of the groove between the two ridges 12, as

will be obvious. The upper member 15 is retained in its cable-clamping position by means of a pair of overhanging shoulders or ears 20 under 1 which the rounded edge 21 of the part 15 is projected, the two acting together after the manner of a hinge. The upper part 15 is preferably provided with a strengthening fin 22 along its back, which projects between the two shoulders 20, and facilitates the positioning of the members to cause the projections of one clamping face to register properly with the depressions in the face of the other. The clamping screw 23 is pivoted to the part 10 on .a transverse pin 24 and projects upwardly through a slot 25 in the upper clampingv member so that the wing nut 26 threaded on the end of the screw and working against the upper face or back of the upper clamping member, will force the two together.

To hold the cable in proper position between the clampingmembers there is preferably provided an arm or projection 27 extending from the rear edge of the clamping member 10 in line with the clamping groove 11, the upper face of the arm having a deep V-shaped groove for receiving the covered portion of the wire. The wire is held in the roove by a clamping member 28 overhanging' the arm 27 and with its lower end working in a vertical guide 29 in the side of the projection 27 and held by a clampingscrew 30 projecting through a slot in the part 28 as shown in Fig. 3.

In attaching the connection its stripped end will be laid in the groove 11 and the insulated part clamped securely in place with the clamp 28. The upper clamping member 15 will then be placed over the wire with its edge under the shoulders 20 and the clamping jaws drawn together by means of the clamping screw 23. The action of the jaws tends to compress and shape the wires into a square, the interlocking projections and recesses of the two members preventing the wires squeezing out flat as-would otherwise be the case. By this arrangement the compressed wires form a compact bundle against which suflicient pressure may be exerted by the clamping faces to give an excellent electrical contact sufficient to carry the large amperage necessary for high powered projection lamps, even though the members of the clamp are of iron instead of copper, which heretofore has usually been employed.

My improved terminal will make a good connection with cables of considerable variation in size. The clamp will operate in the same way for any size cable from the largest which will have a cross section of the size of the fully extended jaws to the smallest size with a diameter only slightly greater thanmeans cross section a with interengaging cutaway portions and projections, and means for drawing said members together with their trough shaped faces opposite to vary the cross section of the bore formed between.

them and to thereby clamp the conductor in said bore with any desired degree of pres-' sure, said conductor contacting with each of the clamping members along the entire length of the terminal.

2. In a cable terminal for electrical connectors, the combination of independent clamping members, each member having a V-shaped clamping face with the sides of the V cut away to provide alternate projections and depressions, means for maintaining said members in such relative positions that the projections of one member extend into the depressions of the other, and a screw for positively forcing said members together to clamp the cable between them with any desired degree of pressure, said conductor contacting with each of the clamping members along the entire length of the terminal.

3. In a cable terminal for electrical connectors, the combination of independent clamping members, each member having a V-shaped clamping face with the sides of the V cut away to provide alternate projections and depressions, a hinged connection between said members at one side of their V- shaped faces for maintaining said members in such relative positions that the projections of one member extend into the projections of the other, and ascrew on the opposite side of said V-shaped faces for drawing said members together to clamp the terminal between them with any desired degree of pressure, said conductor contacting with each of the clamping members along the entire length of the terminal.

Signed at New York city, in the county of New York and State of New York, this 14 day of October, 1918.

THEODORE F. UHLEMANN. 

